Be stricter in index routes verifications (#924)

Some verification was added in #722 but for slashes only. Taskcluster is
actually way stricter than that with what it accepts as index keys and
it doesn't prevent task creations when index routes are invalid
(taskcluster/taskcluster#6266).

The regex comes from the service iteself at
https://github.com/taskcluster/taskcluster/blob/62655d84d55680ffb8faa35e7deadee69f389efa/services/index/src/helpers.js#L8

Fixes #883

Author: Eijebong

src/taskgraph/util/verify.py

@@ -235,10 +235,14 @@ def verify_routes_notification_filters(
                 )
 
 
+# https://docs.taskcluster.net/docs/reference/core/index#valid-characters
+INDEX_NAMESPACE_RE = re.compile(r"^([a-zA-Z0-9_!~*'()%-]+\.)*[a-zA-Z0-9_!~*'()%-]+$")
+
+
 @verifications.add("full_task_graph")
 def verify_index_route(task, taskgraph, scratch_pad, graph_config, parameters):
     """
-    This function ensures that routes do not contain forward slashes.
+    This function ensures that index routes would create valid taskcluster index paths
     """
     if task is None:
         return
@@ -247,11 +251,13 @@ def verify_index_route(task, taskgraph, scratch_pad, graph_config, parameters):
     route_prefix = "index."
 
     for route in routes:
-        # Check for invalid / in the index route
-        if route.startswith(route_prefix) and "/" in route:
-            raise Exception(
-                f"{task.label} has invalid route with forward slash: {route}"
-            )
+        if route.startswith(route_prefix):
+            namespace = route[len(route_prefix) :]
+            if not INDEX_NAMESPACE_RE.match(namespace):
+                raise Exception(
+                    f"{task.label} has invalid index route namespace: {route}. "
+                    f"Namespace must match {INDEX_NAMESPACE_RE.pattern}"
+                )
 
 
 @verifications.add("full_task_graph")

test/test_util_verify.py

@@ -211,6 +211,17 @@ def make_task_treeherder(label, symbol, platform="linux/opt"):
             pytest.raises(DeprecationWarning),
             id="routes_notfication_filter: deprecated",
         ),
+        pytest.param(
+            "verify_index_route",
+            make_graph(
+                make_task(
+                    "valid_route",
+                    task_def={"routes": ["index.example.v2.latest.taskgraph.decision"]},
+                ),
+            ),
+            does_not_raise(),
+            id="verify_index_route: valid route",
+        ),
         pytest.param(
             "verify_index_route",
             make_graph(
@@ -226,6 +237,28 @@ def make_task_treeherder(label, symbol, platform="linux/opt"):
             pytest.raises(Exception),
             id="verify_index_route: invalid slash in route",
         ),
+        pytest.param(
+            "verify_index_route",
+            make_graph(
+                make_task(
+                    "invalid_plus",
+                    task_def={"routes": ["index.example.1.0+hotfix1.latest"]},
+                ),
+            ),
+            pytest.raises(Exception),
+            id="verify_index_route: invalid plus in route",
+        ),
+        pytest.param(
+            "verify_index_route",
+            make_graph(
+                make_task(
+                    "invalid_space",
+                    task_def={"routes": ["index.example.some namespace.latest"]},
+                ),
+            ),
+            pytest.raises(Exception),
+            id="verify_index_route: invalid space in route",
+        ),
         pytest.param(
             "verify_task_dependencies",
             make_graph(